Revivifying adsorbent materials



H.. H. GROSS REVIVIFYING ADSORBENT MATERIALS April 9, 1935.

Filed Oct. 20, 1932 Ill! L HOW/7P0 a 64 056 11v VENTOR HAS A TTOR NE Y Patented Apr. 9, 1935 PATENT OFFICE 1,997,174 REVIVIFYING ADSORBENT MATERIALS Howard H. Gross, Beacon, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application October 20,

9 Claims.

This invention relates to methods of treating decolorizing earth or clay or equivalent material which has been used in the treatment of hydrocarbon oils, and contemplates a process of removing adsorbed coloring matter, polymers and oil from the pores of the earth or clay and the rejuvenation of the adsorbent and ,decolorizing qualities thereof.

It has been generally recognized that the coloring element in hydrocarbon oil consists of asphaltic material which is finely dispersed therein, and when filtering such oils to improve the color, the asphalt-like material is selectively adsorbed on the surface and in the pores of the 1.3 filter medium. The action of the decolorizing earths and clays is not, however, limited to merely adsorbing coloring materials but, in many cases, extends to a polymerization of unstable, unsaturated compounds present in the oils and the subsequent adsorption of the polymers formed in this way.

In the case of decolorizing earths of the type of fullers earth which have been used in the treatment of petroleum oils and which have become spent, the adsorbed polymers, asphaltic coloring matters and oil are removed by subjecting the earth to a treatment in which it is burned in a rotary kiln. This burning treatment may be preceded by a naphtha washing and steaming. In the course of the burning operation, the adsorbed materials present in the pores and on the surface of the earth are partially removed by the combined distilling and oxidizing effects of the burning. I

It has been found that a considerable proportion of the adsorbed material present in the pores of the decolorizing earth becomes carbonized and, as a result, the decolorizing and adsorptive efiiciency of the clay is considerably less than its original eiiiciency. It is thus apparent that after several recoveries the clay will have deteriorated to such an extent as to'be of no further use in decolorizing or treating oil.

Although the method of heating or burning, which has just been described, is used in the revivification of fuller's earth, it is entirely unsatisfactory for rejuvenating certain types of clay which now find wide use in the treatment of hydrocarbon oils. These clays are sometimes spoken of as activated clays or acid treated clays, since it is found that in their natural condition they have little or no decolorizing or adsorptive power but, when treated with acid, develop an active structure and, in many cases, are many 55 times more active than the ordinary fullers earth,

1932, Serial No. 638,720.

In the case of these acid treated clays, revivification can not be effected by means of burning or heating since the active structure is extremely susceptible to destruction under high temperature conditions and, in most cases where the 6 spent acid treated clays are subjected to a heat treatment, the clays instead of being revived, are rendered useless. I

The revivification of decolorizing earths both of the class of fullers earth as well as of the acti- 10 vated clays may be accomplished with much greater efliciency by dissolving out the adsorbed polymers, coloring matters and oils by means of a solvent which has no harmful effect upon the structure of the clay itself. I have found that 16 when either type of spent adsorbent is extracted with furfuralthe adsorbed materials which fill the pores and cover the surface, are substantially dissolved out and removed and the adsorbent so treated will be revived to approximately its 20 initial efliciency. Not only furfural alone but mixed solvents containing furfural may be advantageously used for revivifying spent adsorbents. In certain operations, I have found that when furfural is mixed with relatively large proportions of certain cheaper solvents such as ben: 201 and gasoline, the resultant mixture may be used with results almost equal to those obtainable by the use of furfural alone.

The revivification of a spent adsorbent catalyst, with either vfurfural alone or .furfural in, admixture with another solvent, may be greatly facilitated by carrying out the extraction at elevated temperatures and at such pressure as is necessary to maintain the solvents substantially as in the liquid state. Whereas under normal conditions of temperature and pressure, the adsorbent may require extraction with a large volume of solvent to effect reviviflcation, if the process is carried out at relatively high temperatures the time of washing and extracting is greatly short-' ened, resulting in a much more economical re-. covery of the adsorbent material. The exact reason for the increased efliciency of the solvents at elevated temperatures is not known. However, it is believed that the effect of the increased temperature is to lessen the adsorptive power of the clay and in this way assist in the solution of the adsorbent materials by the solvent.

- In the choice of the proper temperature for carrying out the extraction of the adsorbent material from the adsorbent, it has been found that the operation is most readily carried out at a temperature slightly in excess of the temperature at which the adsorbent displays its maxitemperature is in the neighborhood of F., while in the case of the acid treated clays, the temperature may be in the range of from 250 to 350 F. In the practice of the invention it will be found that the characteristics of the clay to be revivified and the petroleum product upon which the clay has been used,'will determine to a considerable degree whether or not it is desirable to use either furfural alone or in admixture with another solvent.

In order to more fully describe the invention, there is given herewith a brief description of a method of carrying out a revivification of adsorbent material by means of iurfural alone or in admixture with other solvents.

A preferred form of apparatus for practicing the invention is illustrated diagrammatically in the-accompanying drawing, Figure 1, wherein the numeral l0 designates a storage vessel for furfural or a mixture 01' Iurfural with benzol or another solvent. drawofl line In controlled by the valve II, which connects the storage chamber with the mixing chamber I3. To the mixing chamber there is also connected the spent adsorbent storage chamber I 4 by means otthe line 15 controlled by the valve l6.

The mixing chamber i3 is fitted with a mechanical agitator l1, whereby the solvent is pre-- liminarily mixed with the spent adsorbent. The bottom of the mixing chamber, which may advantageously have a conical shape, is connected by means of the line l9 controlled by the valve 20 with the inlet side oi. the pump 2 I. This pump discharges through the line 22' into the digester 24. Y

The digester 24 is constructed to withstand high pressures and is supplied with heating coils 25 through which steam or other heating media may be circulated. It is fitted with a mechanical mixing device 38 which serves to efiect intimate contact between the particles 01' the spent adsorbent with the solvent. The bottom of the digester which may, with advantage, be of conical form, is supplied with a drawofi line 28 controlled by the valve 28 which connects the di-.

gester with the inlet side of the pump 38. This pump discharges through the line 3| and the valve 32 into the pressure filter 34.

The pressure filter is used for separating the revivifled clay from the solvent and dissolved impurities. The filtrate from the filter is drawn oil through the line 38 controlled by the valve 31, and is discharged into the coil 38 of the heater 40. The revivified clay, which is separated by the pressure fllter,'is discharged through the line 4| controlled by the valve 42, to a suitable storage (not shown).

' The heater 43 may, with advantage, beat a type wherein filtrate is heated by heat interchange with a liquid heating medium. The dis-v charge end of the coil 38 is connected through the line 44 controlled by the valve 48 with a lower point or the Iractionating tower 48.' This tower may either be packed with tile or else supplied with the conventional bubble caps and trays. Into the bottom 01' the tower there is fitted a discharge line 41 controlled by the valve 48 which connects it with a suitable storage (not shown) for polymers and oil. The top oi! the tower is equipped with a vapor line 48 controlled by the valve 88 which communicates with the cooling coil 82 of the condenser 83. The outlet of this condenser coil communicates This vessel is fitted with a mum efllciency; In the case of iullers earth, the

with the inlet side of the pump 88 through the line 84 controlled by the valve 88, while the discharge side of the pump is connected through the line 88 with the solvent tank I8.

In atypical operation of the process in connection with the apparatus as shown in Fig. 1, furfural or a mixture of furfural with benzol or with some'other solvent, is passed through the line H controlled by the valve i! into the mixing chamber I 3. Simultaneously, a propertioned amount of spent adsorbent is introduced into the mixing chamber I 3 from the spent adsorbent storage tank I4, through the line l8 controlled by the valve 18.

Within the mixing chamber I3, the adsorbent and solvent are thoroughly mixed to form a more or less uniform suspension. This suspension is drawn oil from the bottom of the mixing chamber I 3 through the line I 8 and the valve 28 into the suction side of the pump 2| which is designed 'to deliver the mixture of spent adsorbent and,

solvent into the digester under the proper pressure. Within the digester, the spent adsorbent is thoroughly. agitated with the solvent and, under certain conditions of operation, it may be desirable to maintain the contents of the digester at an elevated temperature which may be as high as 400 F. and under a pressure of from 100 to 200 lbs. per sq. in. Normally, the adsorbed materials present in the spent adsorbent are readily dissolved by the solvent, and only a short time 'of agitation is necessary for substantiallydissolving them. The mixture of spent adsorbent and solvent, having in solution the asphaltic coloring matters, polymers and oils which were adsorbed on the adsorbent, is delivered to the pump 38 through the draw-oil line 28 controlled by the valve 38. This pump serves to charge the mixture to the pressure filter 34 wherein the rejuvenated clay is substantially separated from the solvent and dissolved materials. a

The rejuvenated clay, separated by the filtration operation, is drawn oil from the filter through the line 4| controlled by the valve 42, and passes to suitable storage while the filtrate passes through the line 38 and-the valve 31 into the coil 38 or the heater '40 wherein its temperature may be raised above the boiling point of the .solvent or mixture of solvents. The heated solution leaves. the coil 38 through the line 44 controlled by the valve 48, passes into the fractionating tower 48 wherein substantial vaporization of the solvent or solvents takes place. The unvaporized residuum, consisting oi polymers and oil, which collects at the bottom of the tower, may be drawn oil through the line 4'! controlled by the valve 43. The vapors oi the solvent or solvents are drawn ofl. from the top of the fractionating tower through the vapor line 43 and the valve 88, and pass into the cooling coils l2 or the condenser 83 where they are condensed. The condensate, formed in these coils, passes through the line 84 controlled by the valve 88 to the pump 88 which delivers the solvent or solvents through the line 83 to the solvent storage tank I 8.

In some operations, it may be desirable to eanna such as that described in the above example,

but may be applied in any instance and under any condition where it is desired to remove adsorbed asphaltic coloring matters, polymers or oils from decolorizing or adsorbing materials. So, for example, acid-treated clay which has been used for the contact filtration of lubricating oils, and which has been separated from the oil, may be revivified while it is present within the filter press by subjecting it to a washing with furfural or a mixture of furfural and benzol. Similarly, fullers earth which has become spent in the percolation of medicinal oils or the like may be rejuvenated while it is in situ in the filter chamber by causing furfural to flow through the body of spent clay and in this way to dissolve out the undesirable adsorbed materials.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departim from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. The process or revivifying adsorbent materials spent in refining petroleum hydrocarbon oil which comprisesfextracting adsorbed hydrocarbon material therefrom by treating the adsorbent with a solvent comprising furfural and benzol.

2. The process of revivifying adsorbent materials spent in refining petroleum hydrocarbon oil which comprises extracting adsorbed hydrocarbon material therefrom by treating the adsorbent with a solvent comprising furfural and gasoline.

3. A method of revivifying by treatment with furfural, adsorbent material, containing polymers adsorbed in the refining of petroleum ny drocarbons, which comprises mixing together the adsorbent material and the furfural to term an intimate mixture, subjecting this mixture to filtration to separate the solution of polymers and furfural from the revivified clay, withdrawing the clay and subjecting the solution to distillation to effect the separation of the polymers from the furfural.

4. The-process of revivifying adsorbent material spent in refining petroleum hydrocarbon oils which comprises extracting the adsorbed hydrocarbon impurities therefrom by treating the adsorbent with furfural at a temperature above that at which the fresh adsorbent-displays its maximum adsorptive emciency when employed in the contacting of petroleum hydrocarbon oils.

5. The process of revivifying adsorbent material spent in refining petroleum hydrocarbon oils which comprises extracting the adsorbed hydrocarbon impurities therefrom by treating the adsorbent with furfural at a temperature above that at which the fresh adsorbent displays its maximum adsorptive efficiency when employed in the contacting of petroleum hydrocarbon oils and under such pressure as to maintain the furfural substantially in the liquid phase.

6. The process of revivifying adsorbent materials spent in refining petroleum hydrocarbon oils which comprises extracting the adsorbed hydrocarbon impurities therefrom by treating the adsorbent with a mixture of benzol and furfural at a temperature above that at which the fresh adsorbent displays its maximum adsorptive efliciency when employed in the contacting of petroleum hydrocarbon oils and under such a pressure as to maintain the solvent mixture substantially in the liquid phase.

7. The process of revivifying adsorbent material which has been used in refining petroleum hydrocarbon oil which comprises treating the adsorbent with a solvent comprising fu fural at temperatures from to 400 F. and at superate mospheric pressures from 100 to 200 pounds per square inch, whereby the solvent ,is maintained in the liquid phase. a

I 8. The process of revivifying adsorbent mate rial which has been used in refining petroleum hydrocarbon oil which comprises treating the" adsorbent with a solvent comprising furfural.

9. The process of revivifying adsorbent, material which has'been used in refining petroleum hydrocarbon oil, which comprises treating the adsorbent with a solvent comprising furfural in admixture with another solvent, said mixture having the essential solvent properties of furfural.

' HOWARD H. GROSS. 

